Fuel systems on board vehicles of various types generally comprise a tank for storing fuel, and this tank generally comprises at least one internal component. Conventionally, in the case of plastic tanks obtained by extrusion-blow moulding, such a component is introduced into and attached to the tank, after the manufacture of the latter, through an opening made in the wall of the tank. However, the penetration through the wall of the tank must take into account the sealing requirements laid down by current environmental standards (LEV II and PZEV for example). For this purpose, the reduction in the number and size of the openings in the wall of the tank constitutes a favourable factor in reducing evaporative losses.
One particular case of such accessories is that of noise reduction baffles, the purpose of which is to absorb the noise (“slosh” noise) associated with the waves which may be generated inside the tank when the vehicle accelerates rapidly, brakes, turns, etc. Such baffles are also known as anti-slosh baffles in the jargon of the field.
In order to solve the problem of attaching them to the inside of a tank without having to make an opening/cut therein, it is known to introduce them into the tank at the same time as it is manufactured by extrusion of a tubular parison around such a baffle, and then by blow moulding the parison and by attaching the baffle to this parison.
In such a process, the baffle may be attached to the parison after or before blow moulding of this parison.
One process according to the 1st alternative is described in Application EP 103832 and comprises the following steps:                extrusion of a tubular parison around a baffle held by a support pin;        piercing the parison with a mandrel that is firmly attached to the mould and that takes on the role of a support;        withdrawal of the support pin;        blow moulding of the parison;        attachment of the baffle to the blow-moulded parison using the mandrel;        withdrawal of the mandrel and demoulding of the tank.        
This process therefore has the disadvantage that the parison is pierced outside of the parting line and therefore has an opening which must be resealed in a leaktight manner after demoulding of the tank.
The process described in Application JP 6143396 makes it possible to solve this problem by arranging to attach the baffle to the parison by welding before blow moulding of the parison, specifically due to moving parts in the mould cavities. This process however has the disadvantage that the internal volume of the tank is limited around the baffle since this baffle is welded before blow moulding and therefore limits the expansion of the parison in its vicinity. Similarly, the size of the baffle is limited by the volume of the extruded parison (which is smaller than that of the blow-moulded tank).